Hi all. New to the site and to blacksmithing. I have always wanted to learn, but never had the time. I finally have some time, so I am taking a blacksmithing course at the community college. Time to build a forge. After doing some online research, I have decided that a forced air gas forge is what I want for my first project. I have a propane tank which, when cut, will have a length of approx. 12 inches and a diameter of 12 Inches. Approx internal volume 1357 cu inches without insulation. So....insulation recommendations? Material, thickness/weight? If 1 burner is sufficient for 350 cubic inches, how many burners should I plan for after the proper amount of insulation is added? At this time I don't have any preferences as to single or double burner, but as that may change, I would like to build this forge for the future, even if it is overkill now. As I know nothing about building a forge, any and all advice is greatly appreciated. Thanks !